“Don’t go chasin’ waterfalls,” sang the ladies of TLC in their huge ‘90s hit. But travelers the world over refuse to heed this advice. From Niagara to Yosemite to Iguazú, the world’s waterfalls are nearly as much of a fixture on tourist maps as the Eiffel Tower and Big Ben. And it’s easy to get hooked on these roaring natural wonders.

Bryan Swan, cofounder of the exhaustive World Waterfall Database, became a waterfall junkie after a childhood trip to the fjords of Norway, and he gushes about a cascade’s spiritual effect. “Finding the real big, powerful waterfalls always allows me to connect with certain electrifying primal forces of nature,” he says. “Some waterfalls make these connections a lot more effectively than others do—and not knowing what I’ll encounter is what makes it fun.” Swan takes four or five waterfall-chasing trips a month, and he’s seen almost 3,000 of these cascading marvels to date.

One aspect of waterfalls that even the casual observer will notice is that many of them, even the most famous, have yet to be accurately measured. For instance, Olo’upena Falls, which plummets nearly 3,000 feet on the rugged coastline of Molokai in Hawaii, is probably the tallest waterfall in the U.S. But Waihilau Falls, on Hawaii’s Big Island, holds persistent claim to the title, at 2,600 feet.

Yosemite Falls is often cited as Continental America’s tallest, at 2,425 feet, but according to the World Waterfall Database, it’s probably 150 feet shorter than Washington’s Colonial Creek Falls, which has never been fully measured. It would all be semantics if it weren’t for the bragging rights of tourism boards and travelers alike.

“When Gocta Falls in Peru were ‘discovered’ by the German explorer Stefan Ziemendorff in 2002, it was initially claimed that they were the world’s third tallest,” explains Swan. But at 2,531 feet, Gocta is “one of the most significant waterfalls on the planet, though it probably ends up being around the 14th tallest.”

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Upon setting eyes on Iguazú, Eleanor Roosevelt reportedly exclaimed, “Poor Niagara!” Straddling the border between Argentina and Brazil, Iguazú is actually 275 terraced falls stretched out across more than two miles of rainforested cliffs.

You may not be nearly as obsessed as Swan, but if you want to tour some falls, here are some factors to keep in mind:

• Many falls are seasonal: what usually roars like a tsunami may trickle like a faucet during the dry time of year.

• Some falls are turned on and off like taps due to dams and hydroelectric needs. Case in point: Mardalsfossen, in the southwestern corner of Norway, flows only during the tourist season—June 20 to August 20, 9 a.m. to 9 p.m.

• Waterfalls are classified in 10 levels based on water volume; the most impressive behemoths, like Niagara and Iguazú, are 10s (Niagara’s Horseshoe Falls averages more than 600,000 gallons per second).

• When flowing at their highest volumes, some waterfalls can be obscured by their mists: Victoria Falls in rainy season is often hidden by watery shrouds that can float up 1,000 feet above it.

The following is our list of falls around the globe that are worth a sightseeing trip, due to their impressive heights, incredible scenery, and awe-inspiring power. Prepare to get a little wet.